Alas is an old-fashioned word people use to express sadness, regret, or disappointment about something that can't be changed. When you say alas, you're acknowledging that something unfortunate has happened or that things didn't work out the way you hoped.

You might read in a story: “I studied hard for the spelling bee, but alas, I misspelled the final word.” The alas shows the writer's disappointment while accepting what happened. Or in a fairy tale: “The prince searched everywhere for Cinderella, but alas, she had vanished into the night.”

The word has a literary, somewhat dramatic feel to it. You probably wouldn't say “alas” in everyday conversation unless you were being playful or theatrical. It appears much more often in books, plays, and poetry than in casual speech. Shakespeare used it frequently in his plays, and you'll find it throughout classic literature.

When someone uses alas today, they're often being deliberately old-fashioned or slightly humorous: “I wanted dessert, but alas, we're out of ice cream.” The word adds a touch of drama to ordinary disappointments, making even small letdowns sound more significant and poetic.